i have an array of <65536*8 int8> (all are binary numbers). i want to make the corresponding grayimage having size if 256* 256. how can i do it.

i have an array of <65536*8 int8> (all are binary numbers) . i want to make the corresponding grayimage having size if 256* 256. how can i do it. kindly suggest me.

Answer 1

[Walter Roberson]

as_numeric = bin2dec(char(YourArray + '0'));
YourImage = reshape(as_numeric, 256, []);

[aditya kumar sahu]

image is not created because i have to read its pixel values.

[Image Analyst]

That does not make sense. You do not need to read its pixel values because you said "i have an array" so you already have the pixel values - they're in your array. They are either 0 or 1 since you said it was a binary (logical) array.

If you don't have your array yet (like you said), then where is it???

[aditya kumar sahu]

The logic is correct but i want to read the pixel values using say imread('x.jpg');but i am not finding the image format by this code.

s_numeric = bin2dec(char(YourArray + '0'));
  YourImage = reshape(as_numeric, 256, []);

here 'YourImage' does not create any image ,it just creates the double matrix.when i convert this to uint8 matrix and then to its image its pixels are changing.it should not change.. is my question is clear to you..

[aditya kumar sahu]

just now i seen about intensity image,it only have data matrix but i want to save the intensity matrix in jpeg format.

[Image Analyst]

Then just use imread(). It will create an image. If you don't like the shape, then use reshape

grayImage = imread('x.jpg');
grayImage = reshape(grayImage, 256, []);
imwrite(grayImage, filename);

And you should not use jpg images if you expect to do image analysis on them. Use .PNG instead.

[aditya kumar sahu]

Thank you very much for your patience.but my doubt is still not clear.. i have a double matrix a[256,256].i just want an image from the matrix.when i am using all the above suggestions i am getting it but some pixels of the image is not same to the original pixel..

[Walter Roberson]

as_numeric = uint8(bin2dec(char(YourArray + '0')));
YourImage = reshape(as_numeric, 256, []);

"but some pixels of the image is not same to the original pixel.."

If you wrote out to a JPEG file and did not tell imwrite to use lossless compression, then you would almost always get back a different array when you used imread(). Unless you tell JPEG otherwise it uses lossy compression -- it throws away information that it thinks you don't need. If you do need that information then you should not be using JPEG.

[aditya kumar sahu]

so,if we use jpeg image some loss of information will be there.is it?but what about png and bmp images.

[Walter Roberson]

Yes, writing to JPEG loses information unless you tell imwrite() to use lossless compression. png and bmp do not lose information.